Table 2.

Kinetic constants of HDH and group X ALDH^a

Enzyme	Strain	Km (μM) for:				kcat (min−1) for:		kcat/Km (min−1 μM−1) for:
		VEH	Acetaldehyde	NAD+	NADP+	VEH	Acetaldehyde	VEH	Acetaldehyde
HdhA	P. aeruginosa	8.5 ± 2.2	19 ± 3	210 ± 40	1,700 ± 270	880 ± 80	980 ± 40	104	51.7
rHdhA	P. aeruginosa	52 ± 19	15 ± 3	18 ± 1	670 ± 140	1,500 ± 300	1,510 ± 100	29	104
rHdhB	P. aeruginosa	13 ± 2	15 ± 4	48 ± 8	640 ± 100	1,100 ± 100	1,100 ± 100	88	75
rOaHdh	O. anthropi	16 ± 5	2.7 ± 0.7	124 ± 41	NA	60 ± 4	54 ± 2	3.7	8.9
rPdHdh	P. denitrificans	65 ± 13	18 ± 6	900 ± 180	NA	91 ± 5	97 ± 7	1.4	5.3
rAldB	E. coli	69 ± 15	2.8 ± 0.6	NA	170 ± 20	170 ± 10	160 ± 10	2.5	57
cHdhb	C. palmioleophila	19.5 ± 3.6	14.3 ± 4	195 ± 23c	697 ± 79c	1,260 ± 66	1,180 ± 105	64.4	82.6

^aEnzyme activities were measured at fixed concentrations of either 1 mM NAD(P)⁺ or 1 mM VEH. Data are the means of four experiments (and the standard deviations for K_m and k_cat values). NA, not applicable due to low activity.

^bData from Ito et al. (3).

^cData obtained from double reciprocal plots.